The attack came from hackers using the “CryptoLocker” weapon, a so-called ransomware Trojan virus that encrypts system-wide data files once it has snuck into a computer.

RICHMOND — A particularly insidious computer hacker attack during Thanksgiving week temporarily crippled the operations of a prominent Rhode Island manufacturer. Only now, nearly two months later, said VIBCO Vibrators president Karl Wadensten, has the firm returned to near-normal operations.

“It paralyzed us,” Wadensten said on Friday. “Imagine going into year end and having your systems gone.”

The attack came from hackers using the “CryptoLocker” weapon, a so-called ransomware Trojan virus that encrypts system-wide data files once it has snuck into a computer. File names remain, but the files cannot be accessed without a “key” that only the hackers have. To get the key, the hackers demand ransom — which rises incrementally as deadlines pass.

VIBCO did not pay the ransom, which eventually reached about $20,000, Wadensten said. Instead, his information technology department worked overtime to painstakingly rebuild — from backup sources — his company’s data network.

“The soft cost of money and time we lost here was anywhere from $50,000 to $75,000,” said Wadensten.

The president said VIBCO’s network consists of more than 100 separate machines — all of which were apparently infected after the virus entered through just one.

When the virus hit, “the whole thing went boom. We were done. We were writing orders on paper and pencil. It was just absurd.”

Today, said Wadensten, “we’re at about 95 percent.”

The CryptoLocker virus was first reported in September. According to Raleigh, N.C.-based Petronella Technology Group, which markets protection software, “at least several million dollars and countless terabytes of data have been lost to the CryptoLocker virus, which at last count had infected more than 250,000 computers.” The Swansea, Mass., police were attacked last month and paid a $750 bitcoin ransom to resume access to data.

Since September, some virus-protection systems have been updated to defend against it, but experts say the best possible protection is smart data backup — on a system that is separate from a network. They also warn not to open unfamiliar attachments, including strange PDF files, apparently favored by the CryptoLocker hackers.

Wadensten, who also serves on the board of the Rhode Island Commerce Corporation, and Fritz Coyro, VIBCO’s head of IT operations, shared their story in the hope that it will be a cautionary tale for other companies — and individuals.

“It was a big undertaking to bounce back,” said Coyro. “We’ve also made some adjustments on how we back up (data). We learned as well. It’s really important that companies take a look at the costs associated with backing up and keeping your environment tight.”